Roasting-furnace.



PATENTED OCT. 17, 1905. F. E. MARUY.

ROASTING FURNACE.

APPLIOATION FILED JUNE 12,1905.

. 2, FD M 5 A 7/ m ,i 1W5 L F W .2 z E a i 5 3 UNI ED STATES FFICE.

Parana ROASTlNG-FUBNACE.

Specification of Letters Patent.

Patented Oct. 17, 1305.

Application filed June 12,1905- Serial No. 264,833.

To all whmn it may concern.-

Be it known that I, FRANK E. MARoY, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Roasting-Furnaces, of which the following is a full, clear, and exact description, reference being had to the ac comp anying drawings, forming a part hereof.

My invention has relation to improvements in roasting-furnaces; and it consists in the novel details of construction more fullyset forth in the specification and pointed out in the claims.

In the drawings, Figure 1 is a middle vertical section of a portion of a furnace, showing one form of my invention applied thereto. Fig. 2 is a horizontal section on line 2 2 of Fig. 1. Fig. 3 is a horizontal section on line 3 3 of Fig. 1. Fig. 4 is a vertical section on line 4 4 of Fig. 1. Fig. 5 is an end view of a rabble-arm, showing a modified construction of dust-deflecting plate; and Fig. 6 is a similar view showing still another modification of dust-deflector.

The present invention relates to that class of ore-roasting furnaces which are provided with a series of superimposed hearths in which the material on one hearth is raked off onto the next hearth beneath until at the conclusion of the roasting operationit reaches the bottom hearth of the series, whence it is removed for further treatment. The Mc- Dougall is one of the forms of furnace here referred to, though of course my present in vention is not to be restricted thereto, nor in fact to ore-roasting furnaces specifically. In the dropping of the material or charge through the central and marginal openings of the respective hearths to the hearths beneath the dust produced by and incident to such dropping or discharge and to the raking of the ore after discharge rises and in a measure adheres to the roof of the upper hearth or the hearth from which the discharge takes place. This adhesion in time forms accretions which are conventionally termed secretions or bearings, which from time to time must be borne ofi. To do this, the furnace must be closed down periodically, entailing the loss of considerable time and increasing the running expenses of the plant. It is the object of my present invention to prevent the formation of these accretions by preventing the deposit of the dust on such upper hearth. This I accomplish by providing the rabble-arms with an extended plate or surface adapted to come directly over the discharge-openings, said plate or sur face deflecting the dust or intercepting it before it reaches the upper hearth. Whatever accretions form on the extended surface aforesaid can be remove or borne off from time to time through the furnace-doors without closing down the furnace.

In detail the invention may be described as follows:

Referring to the drawings, F represents a furnace of the McDougall type well understood in the art. The hearths are represented by h and may be of any number; but as any consecutive pair of hearths will suffice for a description of the present invention only two such hearths are herein shown. Passing through the several hearths is a rotatable rabble-shaft 1, from which radiate the series of rabble-arms 2, extending into the several hearths and carrying rakes or blades 3, by which the material is successively fed from one hearth to the hearth immediately beneath it,'all as fully understood in the art. The rakes of the respective hearths are set to advance the ore toward the central openings 4 of one series of hearths, through which the ore drops onto the hearths below, whence it is raked through the marginal openings 5 of the second series to drop again onto the hearths of the first series. This is well understood in the art and is only briefly adverted to herein in order to bring out the purpose of my invention.

The arms 2 are preferably disposed directly over one another throughout the several hearths, as shown, the blades 3 at the inner ends of the arms raking the ore toward the central openings 4 and the blades at the outer ends of the arms raking the ore toward the marginal openings 5, being provided with lateral projecting wings or extensions 3, which form suitable extended intercepting and deflecting surfaces against which the dust impinges and on which it deposits and in time forms accretions which can be removed through the doors D of the furnace. In Fig. 4 I have shown by arrows the path of the dust as the same is deflected after impinging on the outer wings 3 of the second hearth h.

It is of course not necessary that the defleeting surfaces or extensions 3 be cast with the rakes. They may, as shown in the modification in Fig. 5, be hooked on the rabble-arm, Where 6 represents such Wings and 2 the rabblearm, or, as shown in the modification in Fig. 6, the Wings or plate 7 may rest directly on the rabble-arm 2, being shrunk or otherwise secured thereto.

Since the dust is deflected or intercepted by the extended plate formations or Wings, it will partially deposit on the plate and in part dissipate throughout the hearth, and the accretion formed by the consecutive deposits may, as stated above, be removed or borne off from time to time through the doors of the furnace.

The inner set of deflecting surfaces or wings 3, while shown specifically attached to the rabble-arms, may so far as the present invention is concerned be carried. by and in any mechanical manner connected to the rabble-shaft, as is obvious to any one skilled in the art. It is to be understood, of course, that not only the dust produced or released by the dropping of the ore through the discharge-openings 4 5 is intercepted by the wings 3, but any dust incident to the raking operation as Well.

Having described my invention, what I claim is 1. In a furnace having a series of superimposed hearths provided with discharge-openings leading from one hearth to the next hearth beneath, means for raking the material through the openings from one hearth to the next hearth, said raking means being provided with surfaces suitably extended for intercepting the dust rising through said openings, substantially as set forth.

2. In a furnace having a series of superimposed hearths provided with discharge-openings leading from one hearth to the next hearth beneath, means for raking the material through the openings from one hearth to the next hearth, said raking means being provided with suitable surfaces adapted to intercept and deflect the dust rising from the charge through said openings, substantially as set forth.

3. In a furnace having a plurality of hearths, a rotatable rabble shaft passing through said hearths, rabble-arms radiating from said shaft and extending into the several hearths, the latter having dischargeopenings' leading from one hearth to the hearth immediately beneath, and suitable formations on the rabble-arms adapted to come opposite the discharge-openings, and intercept the dust rising from the charge as the latter drops through said openings, substantially as set forth.

4. In a furnace having a plurality of hearths provided with discharge-openings leading from one hearth to a hearth beneath for the passage of the material, rabble devices adapted to rake the material through said dischargeopenings, and suitably-extended surfaces on said rabble devices adapted to intercept the dust rising from the charge, substantially as set forth.

5. In a furnace having a plurality of hearths provided with dischargeopenings leading from one hearth to the next hearth beneath, a rotatable rabble-shaft passing through the hearths, rabble-arms radiating from said shaft and extending into the several hearths, and suitably-extended formations or surfaces on the arms adapted to travel over the discharge-openings and intercept the dust rising from the material discharged therethrough, substantially as seforth.

6. In a furnace having a plurality of hearths provided with discharge-openings leading from one hearth to the next hearth. beneath, a rotatable rabble-shaft passing through the hearth, rabble-arms radiating from said shaft and extending into the several hearths, rakes or blades on said arms, and wings carried by the rakes traveling over the discharge-openings for intercepting the dust rising from the material discharged through the openings, substantially as set forth.

In testimony whereof I affix my signature Witnesses:

GEORGE BAIZ, H. W. DENNISON. 

